Predictors of asymmetric dimethylarginine levels in patients with rheumatoid arthritis: the role of insulin resistance

Abstract

Objective: To determine whether demographic, inflammatory, and metabolic factors predict elevated asymmetric dimethylarginine (ADMA) levels in rheumatoid arthritis (RA).

Method: A total of 67 RA patients [mean age 56 ± 12 years, median disease duration 8 (3–15) years] were assessed. Routine biochemistry tests, lipid profile, glycaemic profile [glucose, insulin, homeostasis model assessment (HOMA), quantitative insulin sensitivity check index (QUICKI)], and inflammatory markers were measured in all patients. ADMA levels were measured by enzyme-linked immunosorbent assay (ELISA). Regression analyses were performed to identify predictors of ADMA in RA.

Results: Regression analysis revealed that HOMA (β = 0.149, p = 0.003) was an independent predictor of ADMA in RA. From the drug factors, anti-hypertensive medication use was associated with lower ADMA levels (β = −0.081, p = 0.004). ADMA was not associated with RA disease-related parameters or any of the other cardiovascular risk factors that were assessed.

Conclusions: HOMA, a strong indicator of insulin resistance, seems to be the main predictor of elevated ADMA levels in RA patients; ADMA may reflect an important pathway linking abnormal insulin metabolism with endothelial dysfunction in RA.

Acknowledgements

TD has received an educational grant from the European League Against Rheumatism (EULAR) and has been supported by the Rheumatology Society of Northern Greece and the Hellenic Society for Rheumatology. AS was supported by a PhD scholarship from the University of Birmingham.